As with the Macintosh version, menus can be installed in and removed
from the menu bar by sending them the :install and
:remove messages. The File and Edit menus
that appear in the menu bar on startup are Lisp menus. They are the
values of the global variables *file-menu* and
*edit-menu*. The third menu, the Windows menu, is
part of the MDI interface and is not a Lisp menu; you cannot
change or remove it.
When a graphics window is the front window and you select the
Copy item from the Edit menu, a copy of the graph
is placed in the clipboard. This is done by turning on buffering,
sending the window the :redraw message, copying the contents
of the buffer to a bitmap, and placing that bitmap in the clipboard.